1. Field of the Invention
This invention is related to a non volatile semiconductor memory device which includes a voltage transfer circuit which transfers a high voltage within every operation such as write (program) erasure and read.
2. Description of the Related Art
A high voltage (below referred to as [Vpp]) which is higher than a power supply voltage (below referred to as [Vdd]) is generated aside from the power supply voltage to be used in operations such as data program, erasure, and read. Conventionally, a boost voltage circuit for boosting Vdd, and a voltage transfer circuit or a decoder circuit for selectively transferring Vpp are needed in a non volatile semiconductor memory device in order to generate the high voltage used in above mentioned operations.
As an example of a transfer circuit, a Level Shifter which is comprised of a HVP (high voltage P type transistor) is known. A P type transistor is used because unlike an N type transistor it is possible to transfer a voltage without a drop in voltage at the time of transfer.
However, because a process to manufacture a transistor with a high resistance is needed for the Level Shifter which is comprised of a conventional HVP, there are more steps of a production process to make manufacturing costs high (see, for example, Japanese Laid-Open patent Publication No. 2002-63795).